Junior Subordinated Debentures and Other Borrowings - Additional Information (Detail) (USD $)	12 Months Ended			1 Months Ended	12 Months Ended
	Dec. 31, 2012	Feb. 28, 2010	Mar. 17, 2004	Feb. 28, 2010 Line of Credit	Dec. 31, 2012 Line of Credit
Debt Instrument [Line Items]
Issue of floating rate junior subordinated debentures			$ 6,000,000
Issuance date of junior subordinated debentures	Mar. 17, 2004
Maturity of debentures	10 years
Interest rate on debenture	2.54%
Frequency of interest payment	Quarterly
Debt instrument interest rate description	3-month LIBOR plus 2.54%
Effective interest rate	2.85%
Accrued interest on debenture	454,000
Line of credit		5,000,000
Line of credit borrowing capacity		5,000,000
Minimum interest rate on line of credit					6.00%
Increase in interest rate				0.05
Payment date for line of credit	Mar. 17, 2014			Jul. 31, 2010
Accrued interest on the line of credit	$ 1,400,000